1. Field of the Invention
The invention concerns a process for the production of a hollow chamber plate of synthetic material by combining two flat layers of synthetic material, with a large number of webs arranged vertically between the flat layers.
2. Discussion of the Background
Hollow chamber plates which are made of synthetic material are primarily produced by extrusion, see DE-OS No. 15 04 800 and 16 09 777. It is known from CH-PS No. 457 829 and DE-OS No. 32 38 370 to extrude hollow chamber plates with webs that have waves parallel to each other by means of oscillating core pieces in the extrusion nozzle. It is also possible, according to DE-OS No. 25 36 462 to produce hollow chamber plates in one piece with webs having opposing waves by the subsequent expansion of a hollow chamber plate, extruded with varying thicknesses of the outside wall. According to DE-OS No. 20 50 969 hollow chamber plates with webs running at a slant to the extrusion direction can be produced by the simultaneous extrusion of a smooth synthetic material layer and a second synthetic material layer with webs that stand vertically on it and run at a slant to the extrusion direction. The two layers are subsequently combined in the thermoplastic state. In this process the webs run parallel to each other. According to DE-PS No. 20 27 836 a smooth synthetic material layer is joined to a second layer which has vertically arranged webs, preferably set in a grid, after the melting of the web heads.
The process according to DE-PS No. 25 56 016 permits the production of hollow chamber plates with arbitrarily arranged webs by gluing together separately produced cover layers and webs.